Electric signal system



Jan. 7, 1930. T, H THGMAg 1,742,425

ELECTRIC SIGNAL SYSTEM Filed Aug. 8, 1927 i m i II "-T E Lo 3 t9 INVENTOR THoMAs HrrHoMAs BY *5:- W 0O ATTORNEY I-QM Patented Jan. 7, 1930 UNITED STATES PATENT OFFICE THOMAS H. THOMAS, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO THE WESTING- HOUSE AIR BRAKE COMPANY, OF WILMERDING, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA ELECTRIC SIGNAL SYSTEM This invention relates to signal systems, and more particularly to an electric signal system adapted for use on railway trains.

An object of my invention is to provide an electric train signalsystem by the use of which a trainmanmay signal the engineman from any car of a train and by which the engineman may transmit his reply signal to the car station from which the trainmans signal originated and further, by which, the engineman, if he so desires, may signal all of the car stations on the train.

In the accompanying drawing, the single figure is a diagrammatic view of an electric signal system embodying my invention.

As illustrated in the accompanying drawing, the locomotive or controlled car of a train, may be provided with an electric battery 1 or any other suitable electrical supply source, a suitable signal indicating device, such as a buzzer 2 and an enginemans switch having an arm 3 operable to make electrical contact with one or the other of two contact points 4 and 5 of the switch, such arm being normally held out of engagement with both of said contact points by springs 6 or any other suitable means.

The negative terminal of the battery 1 is connected to ground at 7, while the positive terminal isconnected, by a wire 8, with the contact point 4 of the enginemans switch. The contact point 5 of this switch is connected, by a wire 9 with ground at 10 and the switch arm 3 is electrically connected with a train wire 11 at all times. The buzzer 2 may be of the ordinary type and has one of its terminals connected to the train wire 11 and its opposite terminalconnected to the wire 9 leading to ground.

Each of the cars of a train may be provided with an electric battery 12 or any other suitable electrical supply source, a suitable signal indicating device, such as the buzzer 13, a rectifier 14'which permits the flow of electrical current in the direction as indicated by the arrow in the drawing, and a switch device 15.

The switch device 15 comprises a casing 16 containing a sliding contact member 17, which member is provided with an operating stem 18 adapted to be operated, in one direction, by a lever 19 having operating arms 20 and 21, each having an operating cord 22 attached thereto. This lever 19 is adapted to fulcrum around pins 23 and 24 which are so disposed and mounted in the casing, that when the arm 20 is operated the lever turns about the fulcrum pin 23 and depresses the stem 18, and when the lever turns about th pin 24 it depresses the stem 18.

The contact member 17 isprovided with contacts 25 and 26 insulated from each other. This member is normally maintained in the position shown in the drawing by the action of a spring 27. When the member 17 is moved by the lever 19, a predetermined distance, a yielding stop member 28 is engaged thereby, said stop member being subject to the pressure of a spring 29 mounted in the casing 16. In order to prevent rotative movement of the contact member 18, the casing 16 is provided with a pin 30 which engages in a groove 31 formed in the member.

From the train wire 11 there is a branch wire 32 which leads to a terminal contact 33 in the casing 16, in which wire, the rectifier 14 is interposed. Between the rectifier 14 and the terminal contact 33, one terminal of the buzzer 13 is connected with the wire 32, the other terminal being connected to the ground at 34.

From the positive terminal of the battery 12 there is a wire 35 which leads to a terminal contact 36 positioned in the casing 16 adjacent the terminal contact 33. Adjacent the con tact 36 there is also positioned in the casing, a terminal contact 37 which is connected to ground at 38.

The negative terminal of the battery 12 is connected by a Wire 39, with a terminal contact 40 positioned in the casing 16. Adjacent the terminal contact 40 there is positioned in the casing 16, a contact terminal 41, which is connected with the train wire 11 by a wire 42.

The contact 25 on the contact member 17 controls the circuit wires connected to the terminal contacts 33,36 and 37, and the contact 26 controls the circuit wires connected to the terminal contacts 40 and 41.

Assuming the several parts of the signal system to be in their normal positions, as shown in the drawing, and it-for any reason the trainman desires to signal the engineman, the trainman pulls the cord 22, which causes the lever 19 to operate to depress the stem 18 and contact member 17 a suilicient distance that one end of the member 17 engages the upper end of the stop member 28, in which position the contact member 25 will electrically connect the terminal contacts 36 and 37, thus grounding the positive terminal of the battery 12. In this position of the contact member 17 the contact 26 will electrically connect the contact terminals 10 and 41, thus connecting the negative terminal of the battery with the train wire 11. This circuit is completed through the wire 11 and buzzer 2 to ground at 10 which causes the buzzer 2 on the locomotive to sound.

Now if the trainman wishes to receive a reply signal from the engineman he causes the contact member 17 to be further depressed to a position in which the contact 25 will disconnect the terminal contacts 36 and 37 and connect the terminal contacts 36 and 33, and thecontact 26 will continue to connect the terminal contacts l0 and 41. The buzzer 2 on the locomotive and the buzzer 13 on the car from which the signal originated are thus connected in series with the battery 12 on the car and as the combined resistance of these buzzers is too great to be overcome by the energy of the battery, neither buzzer will sound.

If the engineman desires to reply to the trainmans signal and he desires the signal to be sounded only at the car station from which the signal originated, he causes the switch arm 8 to contact with the contact 5 of the switch, thus connecting the negative terminal of the battery 12 to ground at 10. The electric circuit being thus shunted, the buzzer 2 will be eliminated from the circuit and will offer no resistance to the electric current so that the buzzer 13, on the car, will be permitted to sound.

After the trainman has signalled the engineman, he may if he so desires, release his pressure on the cord 22 and permit the contact member 17 to return to its normal position, as shown in the drawing, and then insert a double plug 43 in double jack M which will control the electrical circuit in the same manner as the contacts 25 and 26 do, when the contact member 17 is in its lowermost position. The trainman, after he has received the enginemans signal, removes the plug 43 from the jack 4: 1 which will control the circuit in the same manner as the contacts 25 and 26 control it when the trainman releases the cord 22 and permits the contact member 17 to move to its normal position.

Should the engineman desire to signal every car signal station, he moves the switch arm 3 into contact with the contact point -l of the switch which connects the positive terminal of the battery 1 with one terminal of each of the buzzers 2 and 13 and as the negative terminal of this battery as well as the remaining terminals of the buzzers are connected to ground, a circuit is completed through all of the buzzers and all of them will sound. When the switch arm 3 is in contact with the contact point 4, current flows from the positive terminal of the battery 1 to the train wire 11 over Wire 8 and switch arm 3, and from the train wire 11 current flows through the buzzer 2 and Wire 9 to ground 10, operating the buzzer. From the train wire 11 current flows over the wire 32, through the rectifier 14 and through the buzzer 13 to ground 34, thus operating the buzzers 13 throughout the length of a train.

The rectifier 1 1 is interposed in the wire 32, so that should the voltage of the battery 12 on one car he in excess of that on another car, there will be no possibility of a reverse flow of current from the excess voltage car, back through the batteries of other cars in which the battery voltage is less. When the device 15 is in its second position, i. e., in position that the engineman may signal the trainman, the rectifier 14- also prevents the short circuiting of the battery 12 through the Wire 35, contact 25 of the switch device 15, wire 32, train wire 11, wire 42, contact 36 of the switch device, and wire 39.

Having now described my invention, what I claim as new and desire to secure by Letters Patent, is

1. In an electric signal system, the combination with a signal device on each vehicle of the train and each signal device having one terminal grounded and a train wire per manently connected to the other terminal of each signal device, of a source of current on each vehicle, the source of current on the head vehicle being grounded, means on the head vehicle for either connecting the train wire to the source of currenton the head vehicle or to ground, and means on each of the other vehicles for connecting the local source of current into circuit with the corresponding signal device and said train wire.

2. In an electric signal system, the combination with a signal device on each vehicle of the train and each signal device having one terminal grounded and a single train wire permanently connected to the other terminal of each signal device, of a source of current on each vehicle, the source of our rent on the head vehicle being permanently grounded and the source of current on each of the other vehicles normally disconnected from ground, a switch device on the head vehicle adapted in one position to connect said train wire and signal indicating devices in circuit with the source of current on the head vehicle, and adapted in another position to connect said train wire to ground, and

a switch device on each of the other vehicles operative to connect the local source of current into circuit with the corresponding signal device and said train wire.

3. In an electric train signal system, the combination with a train wire, of an electrically controlled signal indicating device on one car of a train, an electrically controlled signal indicating device on each of the other cars or" the train, each of said signal indicating devices being permanently connected to said train wire and to ground, a source of current on each of said cars, the source of current on the first mentioned car being permanently grounded and the source of current on each of said other cars being normally disconnected from groun l, a switch device on each of said other cars operative to one position to connect the local source of current to ground and to said train wire to complete a circuit through the signal indicating device on the first mentioned car, and operative to another position to connect the local signal indicating device and the signal indicating device on the first mentioned car in series with the local source of current, and a switch device on the first mentioned car operative to either shunt the signal indicating device on the first mentioned car out of circuit or connect both of said signal indicating devices in parallel with the source of current on the first mentioned car.

4. In an elec ric train signal system, the combination with a single train wire, of an electrically controlled signal indicating device on one car of a train, an electrically controlled signal indicating device on each of the other cars of the train, each of said signal indicating devices being permanently connected to said train wire and to ground, a source of current on the first mentioned car permanently connected to ground, a source of current on each of said other cars normally disconnected from ground, a switch device on each of said other cars operative to connect the local source of current to ground and to said train wire to operate the signal indicating device on the first mentioned car, and a switch device on the first mentioned car operative to connect the grounded source of current on the first mentioned car in parallel with all of said signal indicating devices.

5. In an electric train signal system, the combination with a train wire, of an electrically controlled signal indicating device on a car of a train, an electrically controlled signal indicating device on each of the other cars of the train, each of said signal inclicating devices being permanently connected to said train wire and to grounc, a source of current on the first mentioned car permanently connected to ground, a source of current on each of the other of said cars normally disconnected from ground, a switch device on each of said other cars operative to connect: the: local source of current to: groundand' to said train wire to .op'era'teathe signal indicating device .on. the; first"v H1611?- tioned car, and aISWltClLdGVlCB onthefirst mentioned car operativeutoconnect the source: of current on the first mentionedccarto said. train wire to operate all the signal indicating: devices on said other cars.

6. Inan eleetriotrain signal system, the combination with a train wire, of an elec-w trically controlled signal indicating; device; on a car ofsa train, an electrically controlled signal indicating device on each. of the other cars ofthe train, each-of saidsignal indicat 7 ing devicesbeing permanently connected to'.- said train wire and to ground,a sourceof current on the first mentioned lcar'p'ermanently connected to ground, a zsource'of currention each of the other of said cars normally discon' 1 nected from ground, a switch deviceion eachv 85, of said other cars operative'to'a position to connect the local source of current to said: train wire and to ground'to operate the signal indicating device on the first mentioned car, and operative to another position to connects said local source of current to thelocal signal device and to said train wire, and "a switch devicev on the first mentioned'car operative: to a position to connect the source of current on the first mentioned car to said train wire-g to operate all of said si nal indicating devices and operative to another position to ground said train wire to operate thesignal': indicating devices on the car 'whose sw-itch device is in its second mentioned position,

7. In an electric train wire signal system, the combination with a train wire, otfanelec trically controlled signalindicating device'on a carof a train, an electrically controlledin dicating device on'each of the other carsof gv, the'train, each of said signalindicating*de-' vices being connected to said train wire and to ground, a source of current on each car of the train, the source of current on the'fii st' mentioned car being permanently grounded and s the source of current on each of the other cars being normally disconnectedfrom ground, a switch device on each of said cars normally maintaining said sources of current out of circuit with said signal indicating devices, a 115.,

. switch device on the first mentioned car operative to either connect the grounded source of current into circuit with said train wire tooperate all of said signal indicating devices or connect said train wire to ground, and a 120,; switch device on each of said other cars operative to either connect the local source of current to ground and to said train wire to operate the signal indicating device on the first mentioned car or connect said local 125. source of current in series with the local signal indicating device and the signal indicating device on the first mentioned car, the signal device on the first mentioned car being shunted out of circuit when the switch device 130.

on the first mentioned car is operated to connect said train wire to ground causing the local signal device on the car to operate.

8. In an electric train signal system, the combination with a train Wire, of a signal device on one vehicle of a train, a signal indicating device on another vehicle of the train, both of said devices being connected to said train wire and to ground, a source of electric current on each vehicle, the source of current on the first mentioned vehicle being permanently connected to ground and the source on other vehicle being normally disconnected from ground, a switch device on the second mentioned car operative to connect the local source of current to ground and in series with said signal indicating devices, and means on the first mentioned vehicle operative to shuntthe current around one of said signal indicating devices or operative to connect both of said signal devices in parallel with the permanently grounded source of current.

9. In an electric train signal system, the combination with a train wire, of an elec trically controlled signal indicating device at the enginemans station on the train, an electrically controlled signal indicating device at each of the trainmans stations on the train, each of said signal indicating devices being connected to said train wire and to ground, a grounded source of current, an enginemans switch for at one time connecting said source of current in parallel with said signal indicating devices, and at another time for connecting said train wire to ground by shunting out the signal indicating device at the enginemans station, a source of current normally disconnected from ground, and a trainmans switch operative at one time to connect the last mentioned source of current to ground and to the train Wire and at another time to connect the last mentioned circuit in series with said signal indicating devices.

In testimony whereof I have hereunto set my hand.

THOMAS H. THOMAS. 

